1. Field of the Invention
The present invention relates to a bi-directional pressure relief valve for a plate fin heat exchanger.
2. Description of Related Art
Heat exchangers in automobiles are used in heating and cooling systems and may be a radiator, heater core, oil cooler or the like. Some heat exchangers have a symmetrical structure wherein the unit is similar in the front and rear profiles. This produces a situation where the unit may be inadvertently installed in the reverse direction, sometimes providing heat exchange equally well in either direction. A problem arises when the symmetrical heat exchanger has an internal component affected by direction of fluid flow. A pressure relief valve, for example, is used to bypass at least a portion of the fluid flowing to prevent pressure buildup in the heat exchanger. Pressure relief valves are required when the fluid, especially viscous fluids are at or below operating temperatures, such as operating in cold weather conditions. The high viscosity of the fluid creates additional resistance to fluid flow, thereby restricting the flow rate of the fluid. The relief valve is also required whenever the heating or cooling system may be susceptible to pressure spikes.
Pressure relieve valves are used to reduce the restriction (pressure drop) to fluid flow through the heat exchanger. They additionally protect the heat exchanger and the heating or cooling system from pressure impulses (spikes). Pressure relief valves allow bypass in only one direction, allowing no flow in the opposite direction. If the pressure relief valve is installed in a heat exchanger system which has been installed with the flow direction opposite the intended direction, the pressure relief valve will block flow while conditions indicate the relief valve should be in apartially or fully open state. This creates a condition which may cause damage to other components of the heating or cooling system as well as create a safety concern.